STM32CubeMX 4.25 PLL Mux Error ''PLL Mux should have HSE as input''

[John F.]

Posted on April 05, 2018 at 10:21

Using STM32CubeMX 4.25 to configure clock for STM32F767ZI I get PLL Mux Error, 'PLL Mux should have HSE as input' when I choose HSI as clock source. The external clock pins are disabled in the 'Pinout' configuration. The PLL N P Q R values are all good and throw no errors but HSI radio button selection in PLL Source Mux is highlighted with a red square and displays the error message when I mouse hover over. The clock wizard cannot fix it.

Anyone know why please and how to fix this? The ioc file is attached.

Thanks, John F.

#pll

[John F. · Accepted solution]

Posted on April 05, 2018 at 13:15

OK. this has been asked before -

https://community.st.com/0D50X00009XkYorSAF

The reason is that my Project enabled USB and thus had to use the external xtal oscillator.

Disabling USB removes the error and allows code generation. Since I'm only playing around at present, it's no problem to disable USB. In any case, the Nucleo767ZI I target provides an 8MHz clock from the ST-Link STM32 on board so I probably should have configured bypass.